Cliap. 54.] PEAELS. 431 



world; Perimula,^" also, a promontory of India. But those 

 are most highly valued which are found in the vicinity of 

 Arabia/^ in the Persian Gulf, which forms a part of the Bed 

 Sea. 



The origin ^^ and production of the shell-fish is not very dif- 

 ferent from that of the shell of the oyster. When the genial 

 season of the year^^ exercises its influence on the animal, it is 

 said that, yawning, as it were, it opens its shell, and so receives 

 a kind of dew, by means of which it becomes impregnated ; 

 and that at length it gives birth, after many struggles, to the 

 burden of its shell, in the shape of pearls, which vary accord- 

 ing to the quality of the dew. If this has been in a perfectly 

 pure state when it flowed into the shell, then the pearl pro- 

 duced is white and brilliant, but if it was turbid, then the 

 pearl is of a clouded colour also ; if the sky should happen to 

 have been lowering when it was generated, the pearl will be 

 of a pallid colour ; from all which it is quite evident that the 

 quality of the pearl depends much more upon a calm state of 

 the heavens than of the sea, and hence it is that it contracts a 

 cloudy hue, or a limpid appearance, according to the degree of 

 serenity of the sky in the morning. 



If, again, the fish is satiated in a reasonable time, then the 

 pearl produced increases rapidly in size. If it should happen 

 to lighten at the time, the animal shuts its shell, and the pearl 

 is diminished in size in proportion to the fast that the animal 

 has to endure : but if, in addition to this, it should thun- 



^6 See B. vi. c. 23, ^Han, Hist. Anim. B. xv. c. 8, says to the same 

 efiFect, but calls it " Perimuda, a city of India." 



i'^ -3ilian, Hist, Anim. B. x. c. 13. It has been already remarked, in the 

 sixth Book, that the ancients looked upon the Persian Gulf as forming 

 part of the Erythraean or Red Sea. 



^8 The pearl itself, Cuvier says, is nothing else but an extravasation, so 

 to say, of the juices, whose duty it is to line the interior of the shell, to 

 thicken and so amplify it ; and consequently, it is produced by a malady. 

 It is possible, he says, for them to be found in all shell-fish ; but they have 

 no beauty in them, unless the interior of the shell, the nacre, or, as we ciiU 

 it, the mother of pearl, is lustrous and beautiful itself. Hence it is, thai; 

 the finest of them come from the east, and are furnished by tlie kind of 

 bivalve, called by Linnoeus, " Mytilus margaritiferus," which has the most 

 beautiful mother of pearl in the interior that is known. The parts of the 

 Indian sea which are mentioned by Pliny, are those in which the pearl 

 oyster is still found in the greatest abundance. 



^^ All this theory, as Cuvier says, is totally imaginary. 



